Soiled textiles are generally cleaned in one of two ways, i.e. either by washing in water with the aid of suitable adjuvants such as detergents and bleaches or by dry cleaning in an organic solvent such as, for example, perchloroethylene or trichlorotrifluoroethane. The wet washing in an an aqueous medium is normally cheaper but less effective in the presence of oily or fatty stains whose removal requires a high concentration of detergents; the dumping of such a detergent-rich liquor into a sewer contributes greatly to the pollution of the environment. On the other hand, a treatment in an organic solvent requires thorough drying and solvent recovery for economic reasons as well as for environmental considerations.
Certain processes are known in which water and organic solvents are jointly used in the treatment of textiles, e.g. as an emulsion or a micellar solution. The washing of garments or the like in such a medium, however, has not proved very effective inasmuch as graying of white articles cannot be avoided even with prolonged rinsing. Water-soluble soil can be removed only imperfectly with such mixtures.
The use of hot water for the removal of a residue of organic solvent from sheet material subjected to an impregnation process has been suggested in British Pat. No. 812,894. It is also known from U.S. Pat. No. 3,783,560, granted to us jointly with others and partly owned by the assignee of our present application, to dye textiles with the aid of a mixture of organic solvent and water and to rinse the dyed goods in a water bath which is heated to extract the residual solvent by evaporation. No comparable technique, however, has heretofore been applied to the cleaning of textiles as far as we are aware.